1. Field of the Invention
The present invention relates to an apparatus for recording optical information to, and reproducing optical information from, an optical magnetic tape, and to the track structure for such an apparatus.
2. Description of Related Art
Optical magnetic recording has a number of advantages over magnetic recording techniques such as higher recording density, higher reliability due to the lack of contact between the head and recording media, and longer recording medium life. These advantages have made compact disks and laser disks popular. Optical magnetic disks, however, have a limited data capacity making them inappropriate for recordation of video signals or other types of information processing requiring a large capacity. Compact disks (CD) have low data-transmission speeds making the processing of moving pictures difficult. Similarly, a laser disk (LD) can only store approximately one hour of an analog video signal. Therefore, optical magnetic tape which has a large data-capacity is required for digital VCRs having high picture quality.
Conventional apparatus for recording and reproducing optical information using optical magnetic tape have drawbacks. When information is helically recorded on the optical magnetic tape, data-transmission speed is determined by the rotating speed of a drum carrying the optical magnetic tape. Therefore, to achieve a high data-transmission speed, the drum's rotating speed should be high and its size should be large, decreasing stability and increasing noise. Moreover, tracks lengths are long, stretching diagonally across the width of the optical magnetic tape, thereby making it difficult to keep the tape flat for the entire width of the track. Furthermore, since the scanning angle is small, the focal length of objective lens should be long and the diameter of the scanning laser beam should be large, enlarging and/or complicating the apparatus.